---
net/wireless/nl80211.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 6774072e836f..e1707cfd9076 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2496,6 +2496,22 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
rtnl_unlock();
return ret;
}
+
+ /*
+ * auto-detect support for large buffer sizes: af_netlink
+ * will allocate skbufs larger than 4096 in cases where
+ * it detects that the client receive buffer (given to
+ * recvmsg) is bigger. In such cases we can assume that
+ * performing split dumps is wasteful since the client
+ * can likely safely consume the entire un-split wiphy
+ * message in one go without the extra message header
+ * overhead.
+ */
+ if (skb_tailroom(skb) > 4096) {
+ state->large_message = true;
+ state->split = false;
+ }
+
cb->args[0] = (long)state;
}
@@ -2529,6 +2545,7 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
* We can then retry with the larger buffer.
*/
if ((ret == -ENOBUFS || ret == -EMSGSIZE) &&
+ !state->large_message &&
!skb->len && !state->split &&
cb->min_dump_alloc < 4096) {
cb->min_dump_alloc = 4096;
--
2.21.0
